It is the country that has sent members of the punk band Pussy Riot to crumbling prison colonies and its richest man to an isolated northern jail. But Russia met its match on Thursday when it attempted to silence the world's biggest pop star.

Madonna was widely criticised in Russia this summer for voicing support for Pussy Riot during a Moscow concert and speaking out for gay rights during a performance in St Petersburg. A senior official called her a "moralising slut" for the former, and nine claimants brought a $10.7m lawsuit against her for the latter.

On Thursday a court St Petersburg ruled against the plaintiffs, members of various conservative groups who argued that Madonna's comments violated a new law banning the promotion of "homosexual propaganda" to minors and would lead to the destruction of the nation. Violation of the law is punishable by fines of up to 500,000 roubles (£10,000).

During a day-long hearing, the court examined YouTube footage and was shown screenshots of Madonna's Facebook page as proof that the material girl was crazy for gay rights. "I am here to say that the gay community and gay people here and all around the world have the same rights – to be treated with dignity, with respect, with tolerance, with compassion, with love," Madonna said during the performance in August, as concert-goers waved gay pride flags and flashed pink wristbands the pop star had handed out as symbols of support.

The claimants argued that Madonna's performance would adversely affect Russia's birthrate and therefore its ability to maintain a proper army. They cited posts on the Facebook page condemning the law as proof she had prior knowledge of the potential criminality of expressing herself.

Madonna ignored repeated requests to attend the hearing, held in a tiny courtroom in Russia's second city. "St Petersburg's laws were brutally violated," one of the claimants, Marina Yakovlyeva, told the court, news agencies reported. "In the coming years, this type of violation could become the norm. But we have created a precedent – any artist coming to our city will know now what laws exist."

Russia has been harshly criticised over the law, which has also been adopted in eight other regions. Some MPs have floated introducing it on a federal level. Adoption of the law in St Petersburg, long seen as Russia's most westernised city and its cultural capital, has led to a global outcry. All Out, a gay rights group, as called on travellers to boycott St Petersburg. The Canadian government has issued advisories to gay citizens planning to take a holiday there.

The judge in the case, Vitaly Barkovsky, deliberated for more than an hour before delivering his verdict, but appeared to treat the case with scepticism from the start. After one claimant, Vitaly Orlovsky, said Madonna's concert would prompt the divorce rate to skyrocket, Barkovsky asked him why he was suing no alcoholics, since alcoholism was a well-known cause of divorce in the heavy-drinking country.

Vitaly Milonov, a local MP who has led St Petersburg's anti-gay campaign, accused Madonna of showing no respect for the court and said the star's actions answered the question "who's that girl". "You can see what kind of person she is – for her, Russia is a cow from whom she can come and get milk – that is, money – and then leave, while not following our laws," he told the Guardian.